Oil well pump



- H. F. WATKINS June 23, 1931 gall/IA OIL WELL PUMP Filed April 17, 19292000000 ognggog TTORNEYS.

Patented June 23, 1931 UNITED STATES PATENT Fl-ice HAROLD IF. WATKINS,OF OAKLAND, CALIFORNIA ASSIGNOR TO WATKINS INTER- HITTING PUMP COMPANY,OF SAN FRANCISCO, CALIFORNIA, A CORPORATION OF CALIFORNIA on. WELL rum?Application filed April 17, 1929. Serial No. 355,702.

that it pumps the oil with a minimum amount of emulsification, andtherefore it is of particular value when used in connection with wellshaving a considerable flow of water. As is well known, emulsification ofoil is commonly experienced in gas lift pumps of the ejector type, andmakes necessary additional equipment and treating processes to effectde-emulsification' Furthermore such apparatus may cause an accumulationof gas within the well, thus decreasing the flow of oil. WVhi le theapparatus disclosed in said copendlng application No. 27 8,090 issuccessful and operable, I have found that under certain operatingconditions or when operating in wells of a certain character,emulsification may still take place to a certain degree and gas mayaccumulate within the Well.

It is a general object of this invention to devise a pumping apparatuswhich will prevent emulsification of the oil irrespective of theoperating conditions.

It is a further object of this invention to devise a pumping apparatuswhich will give uniform results when'used in different wells or underdifferent operating conditions.

It is a further object of this invention to devise a pumping apparatusof the above character, which will have means for precluding thepossibility of gas or air under pressure accumulating within the well.

Further objects of the invention will appear from the followingdescription in which I have set forth the preferred embodiment of myinvention. It is to be understood that the appended claims are to beaccorded a range of. equivalents consistent with thestate of the priorart.

Referring to the drawings:

Figure 1 isa side elevational view illustrating my apparatus assembledin a typical oil well.

Fig. 2 is a cross sectional detail illustrat- 1ng my valve apparatus inone operating positlon.

Fig. 3 is a view similar to Fig. 2 illustrating the valve apparatus in adifferent operating position.

My invention can be outlined briefly as comprising a pair of pipestrings which extend down into an oil well below the normal level ofoil. Located within the well-and associated with these pipes, there is avalve mechanism which is recurrently operated.

This mechanism serves to control communication between the pipe stringsand to control flow of oil from the well into one of the pipes. Inaddition to this valve mechanism, other means is provided to precludethe possibility of gas under pressure being introduced into the wellproper from the pipe strings, and to prevent such inflow of oil as wouldcause formation of oil emulsion.

Referring to the drawings for a detailed description of my invention, inFig. l I have shown a well 10 within which is extended a pair of pipestrings 11 and 12. These pipe strings are preferably arrangedconcentrically, and one, for example string 11., serves to convey gasunder pressure down into the well and can therefore be termed the gaspipe string, while the other may be termed the oil pipe-string andserves to convey oil to the surface of the well. Associated with thelower portions'of pipe strings'll and 12 and located a substantial.distance below the normal oil level within the well, I

provide valve mechanism 13, the details of which will. be presentlydescribed. At the mon. The construction shown is practical andeffective, and consists of a valve barrel 19 within which is arranged amovable valve member 21. For example the barrel 19 can consist of atubular casing 22 within which is arranged a suitable liner 23. Valvemember 21 is in the form of a hollow tube having a lower closed 'end,and being machined or ground to have a fluid tight fit .with the liner23. Valve member 21 and liner 23 are made of suitable wear resistingmaterial so as to permit operation over long periods without appreciable'wear or leakage. Upper and lower pipe couplings 26 and 27 serve toretain casing 22 and liner 23 assembled, and the upper coupling 26connects with the lower end of pipe string 11.

Extending below the barrel 22 and communicating with the same, I provideone or more pipe sections 29 forming a fluid chamber. These pipesections may be considered as a continuation of the oil pipe string 11.Adjacent the upper end of barrel 19, valve member 21 is provided withone or more gas flow ports 31, and likewise adjacent the lower end ofbarrel 19, valve member 21 is provided with one or more oil flow ports32 In practice, for effecting operation of valves 17, 18, I providemechanical motion applying mechanism at the surface of the well, andthis mechanism preferably serves to effect relative reciprocatingmovements between pipe strings 11 and 12. Thus in Fig. 1 I have shownthe gas pipe string 11 stationary, while the upper end of pipe string 12is connected to an actuating mechanism 34 thru a convenient cable 36. Iprefer in this connection to utilize hydraulic actuating mechanism ofthe type described in my copending application No. 316,163 filed Oct.31, 1928. Such actuating mechanism can be conveniently adjusted so as tovary the stroke of pipe string 12, and to adjust the rate of its up anddown movement.

Assuming that actuating mechanism 34. properly reciprocates the pipestring 12, as valve member 21 approaches the upper limit of its stroke,ports 31 are exposeda ove the barrel 17, to establish communicationbetween pipe strings 11 and 12. On its downward stroke, communicationbetween the two pipe strings is first interrupted and .then after agiven time interval ports 32 are exposed below the lower end of barrel19, to establish communication between pipe 29 and pipe string 12, thruvalve member 21.

In combination with the above apparatus, I prefer to provide valve meansassociated with pipe 29, to control flow between this pi e and the well.This valve is preferably 0 the fluid operated check type and canconwithin the well at this point, ball 39 is re-.

tained upon its seat, but when pressure in the well adjacent this valveis greater than the pressure within pipe 29, the ball is forced awayfrom its seat and inflow of oil occurs.

Generally the oil in pipe 29 contains sufficient gas to allow member 21to reciprocate. However to insure proper elasticity I can provide a gaschamber 41 having a lower open end, and within which gas from the. oilcan accumulate, thus providing a pneumatic cushion.

The operation of my apparatus can be explained as follows: Assuming thatvalve member 21 is being properly reciprocated by the actuatingmechanism 34 at the surface of the well, when this member is at or nearthe bottom of its stroke as shown in Fig. 3, oil from the well will flowpast check valve 35, thru ipe 29, thru valve member 21 and up into t eoil pipe string 12. After such flow has occurredfor an appreciableperiod and a substantial column of oil exists in pipe string 11 aboutthe ports 31, further flow of oil into pipe string 11 is arrested byupward movement of valve member 21. As valve member 21 approaches thelimit of its upward stroke, gas under pressure which exists between pipestrings 11 and 12, blows thru ports 31 and forms a pneumatic istontending to expand upwardly and to orce upwardly the column of oil aboveit in pipe string 12. After this introduction of a charge of gas hasbeen continued for an appreciable period, downward movement ofvalve-member21 interrupts communication thru ports 31, and furtherintroduction of gas is interrupted. By the time ports 32 areagainexposed, condltions may be such that due to the presence of gas inpipe string 12, the pressure within the lower portion of this pipestring and valve member 21 may be considerab greater than the pressureof oil in the we 1 adjacent the oint of its inflow into pipe 29. If thiscon ition exists upon opening ports 32, back flow of gas into the wellproper is prevented by,

check valve 35. Therefore in such event check valve 35 automaticallyremains closed after opening valve 18, until the pressure in the lowerportion of ipe string 12 is reduced sufiiciently, to e ect opening ofcheck valve 35, after which inflow of oil from the well a ain commencesto fill the lower portion 0 pipe string 12. It is therefore evidencedthat if it were not for the check valve 35, a certain amount of gasunder pressure might escape from the valve mechanism and accumulatewithin the well proper. It has been found that such accumulation of gaswithin the well may seriously interfere with the quantity of flow.

In connection with the above apparatus it is to be noted that itoperates more satisfactorily and gives better results than an apparatusutilizing a single positively operated valve 17 in conjunction with asingle check valve 35. The presence of valve 18 positively prevents flowof oil past ports 31, while gas is being blown thru these ports to forma pneumatic piston. If such flow of oil were permitted, as might be thecase under certain circumstances by omitting valve 18, emulsification ofthe oil would occur.

My apparatus has given unusually satisfactory results and can beinstalled in wells of different depths and capacities with equally goodresults. The reciprocation of pipe string is at a relatively slow ratecompared to oil pumps of the past. For example I employ a time periodfor a complete stroke varying from one minute to four hours, compared to18 to 28 strokes per minute used in standard sucker rod pumps. Thetiming period should be adjusted to a value which will give optimumoperation for any one installation and set of operating conditions. Forexample it is dependent upon the depth of the well, the pressure of gasemployed, the natural well flow, the height of the natural oil column,the sizes of casing and pipe employed, the resistance ofiered to theflow of oil being discharged, and other such factors. The apparatus ishighly economical and utilizes a minimum amount of gas and power, forpumping a given quantity of oil.

I claim:

1. In an oil well pump, oil and gas pipe strings extending down into thewell for a substantial distance below the normal level of oil in thesame, said gas pipe string being adapted for connection with a source ofgas underpressure at the surface of the well, a. valve for establishingand interrupting com-' munication between said pipes at a pointsubstantially below said level, means actuated from the surface of thewell for directly applying motion to said valve whereby it isrecurrently opened and closed, a second oil valve adapted to controlflow of oil into said oil pipe from the well, said second valve beinglocated below the first and being adapted to be recurrently operatedresponsive to operation of the first valve, and a third valve associatedwith the oil pipe and serving to control flow between the second valveand the well.

2. In an oilwell pump, oil and gas pipe strings extending down into thewell, for a substantial distance below the normal level of oil in thesame, said gas pipe string being adapted for connection with a source ofgas under pressure at the surface of the well, a valve for establishingand interrupting communication between said pipes at a pointsubstantially below said level, a second valve serving to permit orinterrupt flow of oil from the well into said oil pipe above said firstvalve, common means for positively oppositely actuating said valveswhereby for one period the second valve is open and the first valve isclosed and for another period the first valve is closed and the secondvalve is open, and a check valve interposed between said second valveand communication of the oil pipe with the well, said check valveserving to prevent outflow from said oil pipe into the well.

3. In an oil well pump, oil and gas pipe strings extending down into thewell for a substantial distance below the normal level ofoil in thesame, said gas pipe string being adapted for connection with a source of1gas under pressure at the surface of the wel valve for establishing andinterrupting communication between said pipes at a point substantiallybelow said level, a second valve serving to permit or interrupt flow ofoil from the well into said oil pipe above said first valve, meansactuated from the surface of the well for applying motion to said valveswhereby they are recurrently and oppositel operated, and a check valveassociated wit said oil pipe string a substantial'distance below saidsecond valve, said check valve permitting inflow of oil from the well tosaid second valve but preventing outflow of oil or gas into the well.

In testimony whereof, I have hereunto set my hand.

HAROLD F. WATKINS.

